Recommit r208506: DebugInfo: Include lexical scopes in inlined subroutines.

This was reverted in r208642 due to regressions surrounding file changes
within lexical scopes causing inlining information to be lost.

The issue was in LexicalScopes::getOrCreateInlinedScope, where I was
previously testing "isLexicalBlock" which is false for
"DILexicalBlockFile" (a scope used to represent changes in the current
file name) and assuming it was then a function (breaking out of the
inlined scope path and reaching for the parent non-inlined scopes). By
inverting the condition and testing for "isSubprogram" the correct
behavior is attained.

(also found some weirdness in Clang, see r208742 when reducing this test
case - the resulting test case doesn't apply with the Clang fix, but
I've added a more realistic test case to inline-scopes.ll which does
reproduce the issue and demonstrate the fix)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208748 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 173 insertions, 21 deletions

diff --git a/include/llvm/ADT/STLExtras.h b/include/llvm/ADT/STLExtras.h
index 807ec59061..5b7b88b900 100644
--- a/include/llvm/ADT/STLExtras.h
+++ b/include/llvm/ADT/STLExtras.h
@@ -530,6 +530,13 @@ make_unique(size_t n) {
 
 #endif
 
+template<typename First, typename Second>
+struct pair_hash {
+  size_t operator()(const std::pair<First, Second> &P) const {
+    return std::hash<First>()(P.first) * 31 + std::hash<Second>()(P.second);
+  }
+};
+
 } // End llvm namespace
 
 #endif
diff --git a/include/llvm/CodeGen/LexicalScopes.h b/include/llvm/CodeGen/LexicalScopes.h
index 31d40ff588..31d6872674 100644
--- a/include/llvm/CodeGen/LexicalScopes.h
+++ b/include/llvm/CodeGen/LexicalScopes.h
@@ -21,6 +21,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/IR/DebugLoc.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/ValueHandle.h"
@@ -185,9 +186,7 @@ public:
 
   /// findInlinedScope - Find an inlined scope for the given DebugLoc or return
   /// NULL.
-  LexicalScope *findInlinedScope(DebugLoc DL) {
-    return InlinedLexicalScopeMap.lookup(DL);
-  }
+  LexicalScope *findInlinedScope(DebugLoc DL);
 
   /// findLexicalScope - Find regular lexical scope or return null.
   LexicalScope *findLexicalScope(const MDNode *N) {
@@ -230,7 +229,9 @@ private:
 
   /// InlinedLexicalScopeMap - Tracks inlined function scopes in current
   /// function.
-  DenseMap<DebugLoc, LexicalScope *> InlinedLexicalScopeMap;
+  std::unordered_map<std::pair<const MDNode *, const MDNode *>, LexicalScope,
+                     pair_hash<const MDNode *, const MDNode *>>
+  InlinedLexicalScopeMap;
 
   /// AbstractScopeMap - These scopes are  not included LexicalScopeMap.
   // Use an unordered_map to ensure value pointer validity over insertion.
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index ed8360f205..bbd00eab7f 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -623,7 +623,7 @@ std::unique_ptr<DIE> DwarfDebug::constructScopeDIE(DwarfCompileUnit &TheCU,
   // avoid creating un-used children then removing them later when we find out
   // the scope DIE is null.
   std::unique_ptr<DIE> ScopeDIE;
-  if (Scope->getInlinedAt()) {
+  if (DS.getContext() && DS.isSubprogram()) {
     ScopeDIE = constructInlinedScopeDIE(TheCU, Scope);
     if (!ScopeDIE)
       return nullptr;
@@ -1210,10 +1210,12 @@ DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
     if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
         DISubprogram(DV.getContext()).describes(CurFn->getFunction()))
       Scope = LScopes.getCurrentFunctionScope();
-    else if (MDNode *IA = DV.getInlinedAt())
-      Scope = LScopes.findInlinedScope(DebugLoc::getFromDILocation(IA));
-    else
-      Scope = LScopes.findLexicalScope(cast<MDNode>(DV->getOperand(1)));
+    else if (MDNode *IA = DV.getInlinedAt()) {
+      DebugLoc DL = DebugLoc::getFromDILocation(IA);
+      Scope = LScopes.findInlinedScope(DebugLoc::get(
+          DL.getLine(), DL.getCol(), DV.getContext(), IA));
+    } else
+      Scope = LScopes.findLexicalScope(DV.getContext());
     // If variable scope is not found then skip this variable.
     if (!Scope)
       continue;
diff --git a/lib/CodeGen/LexicalScopes.cpp b/lib/CodeGen/LexicalScopes.cpp
index 46f864ca55..d965968fb4 100644
--- a/lib/CodeGen/LexicalScopes.cpp
+++ b/lib/CodeGen/LexicalScopes.cpp
@@ -104,6 +104,14 @@ void LexicalScopes::extractLexicalScopes(
   }
 }
 
+LexicalScope *LexicalScopes::findInlinedScope(DebugLoc DL) {
+  MDNode *Scope = nullptr;
+  MDNode *IA = nullptr;
+  DL.getScopeAndInlinedAt(Scope, IA, MF->getFunction()->getContext());
+  auto I = InlinedLexicalScopeMap.find(std::make_pair(Scope, IA));
+  return I != InlinedLexicalScopeMap.end() ? &I->second : nullptr;
+}
+
 /// findLexicalScope - Find lexical scope, either regular or inlined, for the
 /// given DebugLoc. Return NULL if not found.
 LexicalScope *LexicalScopes::findLexicalScope(DebugLoc DL) {
@@ -119,8 +127,10 @@ LexicalScope *LexicalScopes::findLexicalScope(DebugLoc DL) {
   if (D.isLexicalBlockFile())
     Scope = DILexicalBlockFile(Scope).getScope();
 
-  if (IA)
-    return InlinedLexicalScopeMap.lookup(DebugLoc::getFromDILocation(IA));
+  if (IA) {
+    auto I = InlinedLexicalScopeMap.find(std::make_pair(Scope, IA));
+    return I != InlinedLexicalScopeMap.end() ? &I->second : nullptr;
+  }
   return findLexicalScope(Scope);
 }
 
@@ -170,21 +180,26 @@ LexicalScope *LexicalScopes::getOrCreateRegularScope(MDNode *Scope) {
 }
 
 /// getOrCreateInlinedScope - Find or create an inlined lexical scope.
-LexicalScope *LexicalScopes::getOrCreateInlinedScope(MDNode *Scope,
+LexicalScope *LexicalScopes::getOrCreateInlinedScope(MDNode *ScopeNode,
                                                      MDNode *InlinedAt) {
-  auto I = LexicalScopeMap.find(InlinedAt);
-  if (I != LexicalScopeMap.end())
+  std::pair<const MDNode*, const MDNode*> P(ScopeNode, InlinedAt);
+  auto I = InlinedLexicalScopeMap.find(P);
+  if (I != InlinedLexicalScopeMap.end())
     return &I->second;
 
-  DebugLoc InlinedLoc = DebugLoc::getFromDILocation(InlinedAt);
+  LexicalScope *Parent;
+  DILexicalBlock Scope(ScopeNode);
+  if (Scope.isSubprogram())
+    Parent = getOrCreateLexicalScope(DebugLoc::getFromDILocation(InlinedAt));
+  else
+    Parent = getOrCreateInlinedScope(Scope.getContext(), InlinedAt);
+
   // FIXME: Use forward_as_tuple instead of make_tuple, once MSVC2012
   // compatibility is no longer required.
-  I = LexicalScopeMap.emplace(
-                          std::piecewise_construct, std::make_tuple(InlinedAt),
-                          std::make_tuple(getOrCreateLexicalScope(InlinedLoc),
-                                          DIDescriptor(Scope), InlinedAt,
-                                          false)).first;
-  InlinedLexicalScopeMap[InlinedLoc] = &I->second;
+  I = InlinedLexicalScopeMap.emplace(std::piecewise_construct,
+                                     std::make_tuple(P),
+                                     std::make_tuple(Parent, Scope, InlinedAt,
+                                                     false)).first;
   return &I->second;
 }
 
diff --git a/test/DebugInfo/inline-scopes.ll b/test/DebugInfo/inline-scopes.ll
new file mode 100644
index 0000000000..310b0404f8
--- /dev/null
+++ b/test/DebugInfo/inline-scopes.ll
@@ -0,0 +1,127 @@
+; REQUIRES: object-emission
+
+; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+
+; bool f();
+; inline __attribute__((always_inline)) int f1() {
+;   if (bool b = f())
+;     return 1;
+;   return 2;
+; }
+;
+; inline __attribute__((always_inline)) int f2() {
+; # 2 "y.cc"
+;   if (bool b = f())
+;     return 3;
+;   return 4;
+; }
+;
+; int main() {
+;   f1();
+;   f2();
+; }
+
+; Ensure that lexical_blocks within inlined_subroutines are preserved/emitted.
+; CHECK: DW_TAG_inlined_subroutine
+; CHECK-NOT: DW_TAG
+; CHECK-NOT: NULL
+; CHECK: DW_TAG_lexical_block
+; CHECK-NOT: DW_TAG
+; CHECK-NOT: NULL
+; CHECK: DW_TAG_variable
+; Ensure that file changes don't interfere with creating inlined subroutines.
+; (see the line directive inside 'f2' in thesource)
+; CHECK: DW_TAG_inlined_subroutine
+
+; Function Attrs: uwtable
+define i32 @main() #0 {
+entry:
+  %retval.i2 = alloca i32, align 4
+  %b.i3 = alloca i8, align 1
+  %retval.i = alloca i32, align 4
+  %b.i = alloca i8, align 1
+  call void @llvm.dbg.declare(metadata !{i8* %b.i}, metadata !16), !dbg !19
+  %call.i = call zeroext i1 @_Z1fv(), !dbg !19
+  %frombool.i = zext i1 %call.i to i8, !dbg !19
+  store i8 %frombool.i, i8* %b.i, align 1, !dbg !19
+  %0 = load i8* %b.i, align 1, !dbg !19
+  %tobool.i = trunc i8 %0 to i1, !dbg !19
+  br i1 %tobool.i, label %if.then.i, label %if.end.i, !dbg !19
+
+if.then.i:                                        ; preds = %entry
+  store i32 1, i32* %retval.i, !dbg !21
+  br label %_Z2f1v.exit, !dbg !21
+
+if.end.i:                                         ; preds = %entry
+  store i32 2, i32* %retval.i, !dbg !22
+  br label %_Z2f1v.exit, !dbg !22
+
+_Z2f1v.exit:                                      ; preds = %if.then.i, %if.end.i
+  %1 = load i32* %retval.i, !dbg !23
+  call void @llvm.dbg.declare(metadata !{i8* %b.i3}, metadata !24), !dbg !27
+  %call.i4 = call zeroext i1 @_Z1fv(), !dbg !27
+  %frombool.i5 = zext i1 %call.i4 to i8, !dbg !27
+  store i8 %frombool.i5, i8* %b.i3, align 1, !dbg !27
+  %2 = load i8* %b.i3, align 1, !dbg !27
+  %tobool.i6 = trunc i8 %2 to i1, !dbg !27
+  br i1 %tobool.i6, label %if.then.i7, label %if.end.i8, !dbg !27
+
+if.then.i7:                                       ; preds = %_Z2f1v.exit
+  store i32 3, i32* %retval.i2, !dbg !29
+  br label %_Z2f2v.exit, !dbg !29
+
+if.end.i8:                                        ; preds = %_Z2f1v.exit
+  store i32 4, i32* %retval.i2, !dbg !30
+  br label %_Z2f2v.exit, !dbg !30
+
+_Z2f2v.exit:                                      ; preds = %if.then.i7, %if.end.i8
+  %3 = load i32* %retval.i2, !dbg !31
+  ret i32 0, !dbg !32
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata) #1
+
+declare zeroext i1 @_Z1fv() #2
+
+attributes #0 = { uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone }
+attributes #2 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!13, !14}
+!llvm.ident = !{!15}
+
+!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.5.0 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [/tmp/dbginfo/inline-scopes.cpp] [DW_LANG_C_plus_plus]
+!1 = metadata !{metadata !"inline-scopes.cpp", metadata !"/tmp/dbginfo"}
+!2 = metadata !{}
+!3 = metadata !{metadata !4, metadata !10, metadata !12}
+!4 = metadata !{i32 786478, metadata !5, metadata !6, metadata !"main", metadata !"main", metadata !"", i32 7, metadata !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 ()* @main, null, null, metadata !2, i32 7} ; [ DW_TAG_subprogram ] [line 7] [def] [main]
+!5 = metadata !{metadata !"y.cc", metadata !"/tmp/dbginfo"}
+!6 = metadata !{i32 786473, metadata !5}          ; [ DW_TAG_file_type ] [/tmp/dbginfo/y.cc]
+!7 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !8, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!8 = metadata !{metadata !9}
+!9 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!10 = metadata !{i32 786478, metadata !1, metadata !11, metadata !"f2", metadata !"f2", metadata !"_Z2f2v", i32 8, metadata !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, null, null, null, metadata !2, i32 8} ; [ DW_TAG_subprogram ] [line 8] [def] [f2]
+!11 = metadata !{i32 786473, metadata !1}         ; [ DW_TAG_file_type ] [/tmp/dbginfo/inline-scopes.cpp]
+!12 = metadata !{i32 786478, metadata !1, metadata !11, metadata !"f1", metadata !"f1", metadata !"_Z2f1v", i32 2, metadata !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, null, null, null, metadata !2, i32 2} ; [ DW_TAG_subprogram ] [line 2] [def] [f1]
+!13 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
+!14 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
+!15 = metadata !{metadata !"clang version 3.5.0 "}
+!16 = metadata !{i32 786688, metadata !17, metadata !"b", metadata !11, i32 3, metadata !18, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [b] [line 3]
+!17 = metadata !{i32 786443, metadata !1, metadata !12, i32 3, i32 0, i32 0, i32 1} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/inline-scopes.cpp]
+!18 = metadata !{i32 786468, null, null, metadata !"bool", i32 0, i64 8, i64 8, i64 0, i32 0, i32 2} ; [ DW_TAG_base_type ] [bool] [line 0, size 8, align 8, offset 0, enc DW_ATE_boolean]
+!19 = metadata !{i32 3, i32 0, metadata !17, metadata !20}
+!20 = metadata !{i32 8, i32 0, metadata !4, null} ; [ DW_TAG_imported_declaration ]
+!21 = metadata !{i32 4, i32 0, metadata !17, metadata !20}
+!22 = metadata !{i32 5, i32 0, metadata !12, metadata !20}
+!23 = metadata !{i32 6, i32 0, metadata !12, metadata !20}
+!24 = metadata !{i32 786688, metadata !25, metadata !"b", metadata !6, i32 2, metadata !18, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [b] [line 2]
+!25 = metadata !{i32 786443, metadata !5, metadata !26, i32 2, i32 0, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/y.cc]
+!26 = metadata !{i32 786443, metadata !5, metadata !10} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/y.cc]
+!27 = metadata !{i32 2, i32 0, metadata !25, metadata !28}
+!28 = metadata !{i32 9, i32 0, metadata !4, null}
+!29 = metadata !{i32 3, i32 0, metadata !25, metadata !28}
+!30 = metadata !{i32 4, i32 0, metadata !26, metadata !28}
+!31 = metadata !{i32 5, i32 0, metadata !26, metadata !28}
+!32 = metadata !{i32 10, i32 0, metadata !4, null}